Knee lock for artificial legs



Sept. 21, 1948. s. A. HlNKLE ETAL 2,449,897

KNEE LOCK FOR ARTIFICJIALLEGS I Filed March 7, 1946 v 2 SheetsSheet 1 I" v Gzomz: A. HINKLE i 37 1 J6 Auras T. Wgezm .BY

Patented Sept. 21 1943 eNrqorrlce 2,449,397- M H KNEE LOCK FOR ARTIFICIAL LEGS George A. Hinkle, New York, and

Alfred T. Weger, Baldwin, N. Y.

Application March 7, 1946, Serial No. 652,682

I 9Ciaims. (01. 3-2)' This invention relates to artificial legs and more specifically to an adjustable locking device'susceptible of fastening a thigh and a shank section of an artificial leg together in an aligned position.

An object of the invention is to provide an adjustable locking means between thigh and shank sections of an artificial leg, I

Another object is to provide a locking device between the thigh and shank sections which can be easily set to provide adjustments of locking ranging from .a state of non-locking through a partially locking state to and including a state of total locking between the sections. I

A further object is to provide an adjustable locking device between the thigh and shank sections which will lock the thigh and shank sections together during portions of a step. I I

Another object is to provide an adjustable lock-.

ing device between the thigh and shank sections which can beadjusted to provide a locking of the sections during different portions of a step.

These and other objects are accomplished by forming an adjustable locking device with a piv oted arm having a hole therethrough normal to.

the pivot and positioning the arm in the thigh section of an artificial leg with an end resting against a seat in the shank section. A line ex;

tending from the heel of the artificial leg through a loop in the front upper part of the shank secei tion across the shank section and through the hole in the arm is attached at its upper end to an adjustable catch in the thigh section, and aspring is provided which functions against the arm,

tending to force it downward against and onto the seat in the shank section. v I

For further comprehension of the invention, and of the: objects and advantages thereof, refer enee will be had to the following description and accompanying drawings, and to the appended claims in which the various novel features of the,

invention are more particularly set forth.

In the accompanying drawing forming .a material part of this disclosure:

Fig. 1 is a side view of an artificial leg equipped with a new and novel adjustable locking device.

Fig. 2 is a rear in Fig. 1. v 1

Fig. 3 is a fragmentary the line 3-3 of Fig. 2.

Fig. 4 is a perspective vievv of an armof the" device.

Fig. 5 is a fragmentary perspective view show ing the arm and a spring and pivot of' the device;

view of the le fi dell/136' erisectional iew along Fig. 6 is a perspective view of an adjustable control and retaining means of the device.

Fig. '7, is a sectional view along the line 1-1 Fig. 10 is a sectional view along the line HI-lll of Fig. 6.

In the drawings and specification, in which like reference numbers indicate corresponding elements, a new adjustable locking means 20 is shown secured to an artificial leg 2|. The leg 2| is provided with a thigh section 22, a shank section 23 and a foot section 24, the thigh and shank sections being secured rotatably together by apivot 25' and the shank and foot sections by a pivot 26.

, The adjustable locking means 2|] i comprised of a locking arm 21, an adjustable control and retaining means 28 and a line 29. The arm 21 is rotatably heldfat its upper end 30 by a pivot 3| mounted within the thigh section 22 at its lower rear end 32, The arm 21 extends downwardly from the pivot 3| and its lower end 33 rests on a seat 34 formed Within the shank section 23 at its upper rear portion 35. The arm 21 rotates about its pivot 3| in th same direction as the shank about the knee, the seat 34 and rear shank wall, however, limiting the clockwise angle of rotation'of the arm. "The pivots 3| and 25 respectively of the'armv and of the thigh and shank sections, the length of the arm 2"! and theposition of the seat 34 are fixed so that when the thigh and shank sections are aligned, the arm 21 can rest on th seat 34 and lock the sections in an aligned position. The arm 27 is provided with ashouldered end or stop 36' and an adjusting screw 31 to aid in fixing the seating position. "In addition, an opening or hole '38 is formedin the arm about midway between its ends and extends completely therethrough in adirection normal to the axis of the pivot. A spring'39'secured at one end to the pivot 3| is coiled about the pivot 3| and presses against'the arm 21 urging it toward the shank and tending to keep the stop 36 against the seat 34.

The adjustable control and retaining mean 28 is comprised of a frame 49 and a slide or catch element 4|. The frame is secured to a side of thethigh section 22 by screws 42 and is provided with a central passageway 43 andslots 44 separated by shoulders 45. Upper surfaces 46' of the 3 shoulders are provided with upwardly extending projections 41. The slide or catching element 4| i formed with a stem 48, a bottom cross bar 49 and a handle 50, the stem fitting slidably in the passageway 43 and the cros bar 49 extending in a pair of opposite slots 44. An under face 5| of the cross bar 49 is prow'ded with a pair of holes 52 positioned to seat on the projections 41 and retain the catch element 4| in position. The elevation or position of the catch element can easily be changed by turning the handle and cross bar ninety degrees, raising or lowering the stem and then turning the handle another ninety degrees to seat the cross bar in a different slot.

The line 29 i secured at one end to an anchor 53 in the heel of the foot section 24, and :at its other end 54 to the under face 5| of the cross bar 49 of the catch element 4| intermediate its ends. The line extends through the hole 38 in the arm 2'1, and between the arm and the heel the line extends through a loop 55 mounted within the upper front part of the shank section 28. As the line 29 extends across the shank section 23 from the loop 55 toward the arm 21, it forms an appreciable angle with the arm 2'1, resting adjacent thereto above the hole 38. The distance from the catch element 4| to the loop 55 via the hole 38 thus depend on the position and direction of the arm, when the arm 21 extends downwardly with the stop 36 hearing against the seat 34, the distance being longest, and when the arm 21 is raised and aligned between the pivot 3| and loop, the distance being shortest.

The location of the catch element 4| in the frame 40 determines and locates the position and direction of the arm 21 and the amount of line 29 available to be consumed by the arm 21 in bending the line, which extends from the catch element 4|, to hole 38, to loop 55, out of its shortest position. When the catch element 4| is in the lowest slots v44, the stop 36 of the arm 21 is seated against the seat 34 and when the catch element 4| is in the upper-most slots v44, the arm 21 is rotated so that the stop 36 is far from the seat 34.

In walking, the foot is pivoted and at certain times, in a step the heel of the foot section 24 is raised and at other times, the heel is normal to the shank section 23. Thus, at certain times in a step, the rotation of the heel decreases the normal distance between the anchor 53 and the loop 55 and provides an excess of. line 29. This excess is immediately consumed by the arm 21, which is rotated downwardly by the spring 39 which continuously tends to seat the" stop 38 against the seat 34 and so look the shank and thigh sections together.

The four sets of slots 44 are so positioned that when the catch element 4| is in the upper-most slot, the line 29 is of such a length that even when the foot is rotated its utmost, not enough slack is available to permit the arm 21 to rotate downwardly and seat the stop 36; when the catch element 4| is in the next to the top slot, an extreme rotation of the root is required to 'provide enough slack to seat the stop 36 and lock the shank and thigh sections; when the catch element 4| is in the next to the lowest slot, the normal rotation of the ,foot provides suiiicient slack so that during most of a normal step, the arm 21 is in its downward Position with its stop '36 seated and the thigh and shank section's locked; when the catch element 4| is in the lowest slot, sufficient slack is available. at all times so that the arm 21 rests continuously with its stop 36 seated against the seat 34 and the thigh and shank sections locked in an aligned position.

Thus, a person learning to use an artificial leg, an aged person or a person walking over difficult terrain would set the catch element 4| in the lowest slot 44 so that the thigh section 22 and shank section 23 would be continuously locked. A more experienced walker, etc., would use one of the intermediate slots 44 when walking in the house or on smooth pavements, providing (1) a lock becoming effective only when the heel comes in contact with the floor or ground, and unlocking as soon as the thigh and shank return to a straight perpendicular position; (2) a lock becoming efiective as soon as the thigh and shank sections come together at each step thus locking the knee before the heel contacts the floor or ground, and keeping it locked until the body leans forward in completing the tep, thus causing pressure on the ball of the foot which is necessary to release the look. In these two positions an automatic locking and unlocking is obtained at each step. An intrepid walker, or a driver of an automobile who feared an accidental locking, would use the top slot 44 at which locking is impossible.

While we have illustrated and described the preferred embodiments of our invention, it is to be understood that we do not limit ourselves to the precise constructions herein disclosed and the right is reserved to all changes and modifications coming within the scope of the invention as defined in the appended claims.

Having thus described our invention, what we claim as new, and desire to secure by United States Letters Patent is:

1. An artificial leg having a shank, a thigh hinged to the shank, a foot hinged to the lower end of the shank, the shank having an internal seat located below the hinge connection between the shank and the thigh, a pendant bar pivoted at its upper end to the thigh below said hinge connection, a spring acting on said pendant bar to shift the same outwardly, a screw carried by the lower end of the bar and adapted to engage said seat, a flexible cord extending through the pendant bar and connected to the heel of the foot, a pulley in said shank providing a guide for said cord, the cord being extended outwardly of the shank, a stop on the upper end of the cord, and means on the outer side of the thigh having vertically spaced sockets adapted to receive the stop, whereby the user may externally adjust said cord.

2. In an artificial leg, comprising thigh, shank and foot sections pivotally joined together, a locking means disposed to lock the shank and thigh sections to prevent pivotal movement thereof, an adjusting screw operatively associated with the locking means and disposed to permit adjustment of the amount of pivotal movement between the shank and thigh section which can occur when the locking means is eiiective, spring means disposed to cause locking action of the locking means, a line extending between the thigh and foot sections and disposed upon being tensioned to prevent locking action of the locking means, adjusting means disposed on the exterior of the thigh section arranged todetermine the angular position of pivotal movement of the foot section at which tension is applied to the cord to prevent action of the locking means,

said adjusting means comprising a frame having a plurality of slots therein, and a catch secured to the line which maybe selectivelypositioned in any one of the slots. r I a 3. In an artificial leg, having hollow thigh, shank and foot sections respectively pivotally attached to one another, an adjustable locking means for locking the thigh and shank sections against relative pivotal movement, comprising a seat formed within the shank section ,at the top thereof rearward of the pivotal connection of the shank section to the thigh section, an arm pivotally mounted within the lower portion of the thigh section and depended into the. top of the shank .section to have its lower end engage said seat, resilientv means urgin said arm into. a pivoted positionto engage said seat, a loop within the shank section forward ofsaid seat, said arm being formed with a hole extended therethrough from front to rear midway of its top and bottom ends, a line having its lower end'anchored within the foot section, its intermediate portion extended upward within the shank section over said loop and through saidhole and its free end extended outward along the side of said thigh section, and means for adjustably anchoring the free end of said line to the side of said thigh section for controlling the tension of said line and pivotal movement of said arm relative to said seat. 4. In an artificial leg, having hollow thigh, shank andfoot sections respectively pivotally attached to one another,- an adjustable locking means for. locking the thigh and shank sections against relative pivotal movement, comprising a seat formed Within the shank section at the top thereof rearward of the pivotal connection of the shank section to the thigh section, an arm pivotally mounted within the lower portion of the thigh section and depended into the top of the shank section to have its lower end engage said seat, resilient meansurging said arm into a pivoted position to engage said seat, a loop within the shank section forward of said seat, said arm being formed with a hole extended therethrough from front to rear midway of its top and bottom ends, a line havin its lower end anchored within the foot section, its intermediate portion extended upward within the shank section over said loop and through said hole and its free end extended outward along the sideof said thigh section, and means for'adjustably anchoring the free end of said line to the side of said thigh section for controlling the tension of said line and pivotal movement of said arm relative to said seat, said resilient means comprising a spring mounted concentrically on the pivot of said arm and having one end attached to said arm and its other end fixedly secured in position.

5. In an artificial leg, having hollow thigh, shank and foot sections respectively pivotally attached to one another, an adjustable locking means for lockin the thigh and shank sections against relative pivotal movement, comprising a seat formed within the shank section at the top thereof rearward of the pivotal connection of the shank section to the thigh section, an arm pivotally mounted within the lower portion of the thigh section and depended into the top of the shank section to have its lower end engage said seat, resilient means urging said arm into a pivoted position to engage said seat, a loop within the shank section forward of said seat, said arm being formed with a hole extended therethrough from front to rear midway of its top and bottom ends, a line having its lower end anchored within the foot section, its intermediate portion extended upward within the shank section over said loop and through said hole and its free end extended outward along the side of said thigh section, and means for adjustably anchoring the free end of said line to the side of said thigh'section for controlling the tension of said line and pivotal movement of said arm relative to said seat, and an adjustment screw extended from the bottom of. said arm and adjustable to control the operative length of said arm.

6. In an artificial leg, having hollow thigh, shank and foot sections respectively pivotally attached to one another, an adjustable locking means for locking the thigh and shank sections against relative pivotal movement, comprisin a seat formed within the shank section at the top thereof rearward of the pivotal connection of the shank section to the thigh section, an arm pivotally mounted within the lower portion of the thigh section and depended into the top of the shank section to have its lower end engage said seat, resilient means urging said arm into a pivoted position to engage said seat, a loop within the shank section forward of said seat, said arm being formed with a hole extended therethrough from front to rear midway of its top and bottom ends, a line having its lower end anchored within the foot section, its intermediate portion extended upward within the shank section over said loop and through said hole and its free end extended outward along the side of said thigh section, and means for adjustably anchorin the free end of said line to the side of said thigh section for controlling the tension of said line and pivotal movement of said arm relative to said seat, and a stop formed on and extended downward from the bottom of said arm to engage and limit pivoting of said arm toward said seat to a position in which the bottom of said arm will be directly over and seated on said seat.

'7. In an artificial leg, having hollow thigh, shank and foot sections respectively pivotally attached to one another, an adjustable locking means for locking the thigh and shank sections against relative pivotal movement, comprising a seat formed witlrin the shank section at the top thereof rearward of the pivotal connection of the shank section to the thigh section, an arm pivotal 'ly mounted within the lower portion of the thigh section and depended into the top of the shank section to have its lower end engage said seat, resilient means urging said arm. into a pivoted position to engage said seat, a loop within the shank section forward of said seat, said arm being formed with a hole extended therethrough from front to rear midway of its top and bottom ends, a line having its lower end anchored within the foot section, its intermediate portion extended upward within the shank section over said loop and through said hole and its free end extended outward along the side of said thigh section, and means for adjustably anchoring the free end of said line to the side of said thigh section for controlling the tension of said line and pivotal movement of said arm relative to said seat, said adjustable anchoring means comprising a frame secured to the side of the thigh section upward from the bottom end thereof and formed with a central vertical passageway and aligned pairs of slots extending from opposite sides of said passageway, and :a catch element having a stem vertically slidable in said passageway and formed at its lower end with a cross bar selectively engageable into an aligned pair of said aligned pairs of slots, said line having its free end secured to said cross bar,

whereby adjustment of said cross bar in said slots will lCOlltIO'l the tension of said line.

8. In an artificial leg, having hollow thigh, shank and foot sections respectively pivotally attached to one another, an adjustable locking means for locking the thigh and shank sections against relative pivotal movement, comprising a seat formed within the shank section at the top thereof rearward of the pivotal connection of the'shank section to the thigh section, an arm pivotally mounted within the lower portion of the thigh section and depended into the top of the shank section to have its lowerend engage said seat, resilient lrneans urging said arm into a pivoted position to engage said seat, a loop within the shank section forward of said seat, said arm being formed with a hole extended therethrough from front to rear midway of its top and bottom ends, a line having its lower end anchored within the foot section, its intermediate portion extended upward within the shank section over said loop and through said hole and its free end extended outward along the side of said tlr'gh section, and means for adjustably anchoring the free end of said line to the side of said thigh section for controlling the tension of said line and pivotal movement of said arm relative to said seat, said adjustable anchoring means comprising a frame secured to the side of the thigh section upward from the bottom end thereof and formed with a central vertical passageway and aligned pairs of slots extending from opposite sides of said passageway, and a catch element having a stem vertically slidable in said passageway and formed at its lower end with a cross bar selectively engageable into an aligned pair of said aligned pairs of slots, said line having its free end secured to said cross bar, whereby adjustment of said cross bar in said slots will control the tension of said line, and means for releasably retaining said cross bar in position within a desired aligned pair of said slots.

9. In an artificial leg, having hollow" thigh, shank and foot sections respectively pivotally attached to one another, an adjustable locking means for locking the thigh and shank sections against relative pivotal movement, comprising a seat formed within the shank section at the top thereof rearward of the pivotal connection of the shanksection .to the thigh section, an arm pivotal ly mounted within the lower portion of the thigh section and depended into the top of the shank section to have its lower end engage said seat, resilient means urging said arm into a pivoted position to engage said seat, a loop within the shank. section forward of said seat, said arm being formed with a hole extended therethrough from front to rear midway of its top and bottom ends, a line having its lower end anchored within the foot section, its intermediate portion extended upward within the shank section over said loop and through said hole and its free end extended outward along the side of said thigh section, and meansi'or adjustably anchoring the free end of said line to the side of said thigh section for controlling the tension of said line and pivotal movement of said arm relative to said seat, said adjustable anchoring means comprising a frame secured to the side of the thigh section upward iroin the bottom end thereof and formed with a central vertical passageway and aligned pairs of slots extending from opposite sides of said passageway, and a catch element having a stem vertically slidable in said passageway and formed at its lower end with a cross bar selectively engageable into an aligned pair of said aligned pairs of slots, said line having its free end secured to said cross bar, whereby adjustment of said cross bar in said slots will control the tension of said line, and means for rel'easably retaining said cross bar in position within a desired aligned pair of said slots, said releasable retaining" means comprising upwardly extending projections formed on the material of said frame defining the bottom of said aligned pair of slots and engageable into complementary holes formed in the bottom face of said cross bar.

GEORGE A. HINKLE. ALFRED T. WEGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,934,210 Sargent..- Nov. '7, 1933 

